Image forming apparatus configured to communicate with network and capable of managing number of print pages

ABSTRACT

An image forming apparatus includes a main body memory, and a controller. A second upper limit information stored in the main body memory indicates an upper limit of a printable page number that the image forming apparatus is allowed to print in a state where the image forming apparatus is in an off-line state. A printed page number information stored in the main body memory indicates a printed page number printed in the off-line state. The controller is configured to: increment the printed page number information by one in a case where the one sheet of paper is printed on one side printing; and increment the printed page number information by two in a case where the one sheet is printed on double-sided printing. The controller is configured to determine whether the printed page number information is greater than or equal to the second upper limit page number.

CROSS REFERENCE TO RELATED APPLICATION

This application claims priority from Japanese Patent Application No.2020-063649 filed Mar. 31, 2020. The entire content of the priorityapplication is incorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates to an image forming apparatus and acontrol method therefor.

BACKGROUND

Services are available for a user of an image forming apparatus suchthat a contract-dedicated consumable item or replaceable part can beused if there is a contract between the user and a service provider.Such service is called a “subscription service”.

There has been known a printer (image forming apparatus) to which thesubscription service is applicable. Such image forming apparatusreceives a credit file from a subscription server. The credit fileincludes information indicating the number of printable sheets specifiedin the contract.

In the case where a subscription service applied cartridge is attachedto the image forming apparatus, the image forming apparatus checkswhether there remains a sufficient amount of credit (that is, the numberof printable sheets) to print the number of pages indicated by the printjob received at the image forming apparatus. When the image formingapparatus determines that there remains a sufficient amount of credit,the print job received at the image forming apparatus is carried out.

SUMMARY

However, with the conventional image forming apparatus described above,in an off-line state where the image forming apparatus is not connectedto the internet, the credit cannot be supplemented to the image formingapparatus from a subscription server. Further, in the conventional imageforming apparatus, whether there remains the sufficient amount of creditto achieve the print process is determined on a print-job basis. Assuch, when the number of printed pages has reached the upper limitnumber of print pages in the midst of printing, determination is madesuch that the remaining amount of credit is insufficient to complete theprint job, with the result that the printing can no longer be executed.For example, in the case where a print job is received instructing toprint 100 pages, printing of 100 pages in its entirety cannot be carriedout although there remains 99 pages worth of credit.

As described, there may occur in the off-line state that the imageforming apparatus cannot carry out printing a received job even thoughthere still remains credit capable of printing some pages whose numberis smaller than that of the pages required to print by the print job.This involves inconvenience for the users, because if the credit isusable on a print page basis, printing can be carried out for a possiblenumber of pages inasmuch as the credit remains.

In view of the foregoing, it is an object of the disclosure to managethe number of print pages when the image forming apparatus is in theoff-line stat without losing the user's convenience as much as it canbe.

In order to attain the above and other objects, according to one aspect,the disclosure provides an image forming apparatus including aninterface, a main body memory, and a controller. The interface isconfigured to communicate with a network. The main body memory isconfigured to store therein a first upper limit information, a secondupper limit information and a printed page number information. The firstupper limit information indicates an upper limit of a printable pagenumber that is defined in accordance with contents of a contract set inthe image forming apparatus. The second upper limit informationindicates an upper limit of a printable page number that the imageforming apparatus is allowed to print in a state where the image formingapparatus is in an off-line state where the interface is incapable ofconnecting with the network. The printed page number informationindicates a printed page number printed by the image forming apparatusin the off-line state. In a state where the interface is in the off-linestate, the controller is configured to perform printing to print one ormore sheets according to a print job. When one sheet is printed, thecontroller is configured to increment the printed page numberinformation by one in a case where the one sheet of paper is printed onone side printing, and increment the printed page number information bytwo in a case where the one sheet of paper is printed on double-sidedprinting. After the printed page number information is incremented, thecontroller is configured to determine whether the printed page numberinformation is greater than or equal to the second upper limit pagenumber.

According to another aspect, the disclosure provides a method forcontrolling an image forming apparatus including: in a state where theimage forming apparatus is in an off-line state where the image formingapparatus is incapable of connecting to a network, causing the imageforming apparatus to perform printing to print one or more sheetsaccording to a print job; when one sheet is printed, incrementing aprinted page number information by one in a case where the one sheet isprinted on one side printing, and incrementing the printed page numberinformation by two in a case where the one sheet is printed ondouble-sided printing, the printed page number information indicating aprinted page number printed in the off-line state; and after the printedpage number information is incremented, determining whether the printedpage number information is greater than or equal to an upper limit pagenumber that the image forming apparatus is allowed to print in theoff-line state.

According to still another aspect, the disclosure provides an imageforming apparatus including an interface, a main body, and a controller.The interface is configured to communicate with a network. The main bodymemory configured to store therein a first upper limit information and atotal printed page number information. The first upper limit informationindicates an upper limit of a printable page number that is defined inaccordance with contents of a contract set in the image formingapparatus. The total printed page number information indicating aprinted page number that are printed. The controller configured toperform printing to print one or more sheets according to a print job.When one sheet is printed, the controller is configured to increment thetotal printed page number information by one in a case where the onesheet is printed on one side printing, and increment the total printedpage number information by two in a case where the one sheet is printedon double-sided printing. After the total printed page numberinformation is incremented, the controller is configured to determinewhether the total printed sheet number information is greater than orequal to the upper limit of the printable page number indicated by thefirst upper limit information.

BRIEF DESCRIPTION OF THE DRAWINGS

The particular features and advantages of the disclosure will becomeapparent from the following description taken in connection with theaccompanying drawings, in which:

FIG. 1 is a schematic diagram showing an arrangement of an image formingapparatus in accordance with a first embodiment of the presentdisclosure;

FIG. 2 is a block diagram showing essential arrangements of the imageforming apparatus, an ink cartridge, and a server in accordance with thefirst embodiment;

FIG. 3 is a flowchart illustrating a flow of a connection monitoringprocess;

FIG. 4 is a flowchart illustrating a flow of a term renewal process;

FIG. 5 is a flowchart illustrating a flow of a print associated processaccording to the first embodiment;

FIG. 6 is a flowchart illustrating a flow of a first print availabilitydetermining process according to the first embodiment;

FIG. 7 is a flow chart illustrating a flow of a print associated processaccording to a modification; and

FIG. 8 is a flowchart illustrating a flow of a second print availabilitydetermining process according to the modification.

DETAILED DESCRIPTION First Embodiment

Hereinafter, one embodiment of the present disclosure will be describedwith reference to FIGS. 1 through 6. The image forming apparatus 1according to the embodiment is configured to be capable of using aconsumable item or replaceable part dedicated by the contract madebetween the user of the image forming apparatus and a service provider.That is, the image forming apparatus according to the embodiment is suchan image forming apparatus to which the subscription service isapplicable.

Hereinafter, it will be assumed that the subscription service has beenapplied to the image forming apparatus 1 (that is, a contract has beenmade) insofar as there is no special description to the contrary.Further, in the following description, all kinds of the consumable itemor replacement part attachable to the image forming apparatus 1 (forexample, ink cartridge 4 to be described later) is assumed to be thosededicated in the contract insofar as there is special description to thecontrary.

Furthermore, in the embodiment, an inkjet printer will be described asone example of the image forming apparatus. However, the image formingapparatus 1 may be other type of printers other than the inkjet printer.For example, the image forming apparatuses 1 encompasses a laserprinter.

<Overall Structure of the Image Forming Apparatus>

FIG. 1 is a schematic diagram showing the structure of the image formingapparatus according to the embodiment. For the sake of convenience, inthe following description, the upper side in FIG. 1 corresponds to theupper side of the image forming apparatus 1, the lower side in FIG. 1the lower side of the image forming apparatus 1, the left side in FIG. 1the rear side of the image forming apparatus 1, and the right side inFIG. 1 the front side of the image forming apparatus 1.

The image forming apparatus 1 is an inkjet printer configured to performprinting on a print sheet P by ejecting ink droplets in accordance withdata. One or more ink cartridges are mounted on a main body of the imageforming apparatus 1. Incidentally, other than the components depicted inFIG. 1, a display section configured from a liquid crystal display orlamp, and an input section such as button may be provided in the imageforming apparatus 1. The liquid crystal display may be integral with atouch panel so as to be operable as the input section.

In the example shown in FIG. 1, the image forming apparatus 1 includes asheet supply tray 20, a sheet supply portion 2, a conveying roller 60, arecording section 3, a discharge roller 62, and a discharge tray 30. Anopening is formed in the front surface of the main body of the imageforming apparatus 1. The sheet supply tray 20 is movably disposed in theopening to be movable in front/rear direction. A plenty of stacked printsheets P is accommodated in the sheet supply tray 20. The print sheet,for example, has a prescribed size. The print sheet P is not limited toa paper medium. For example, the print sheet P may be a medium made fromresin material, such as an OHP sheet.

The sheet feed portion 2 is configured from a sheet feed roller 21, asheet feed arm 22, and a shaft 23. The sheet feed portion 2 operates insuch a manner that the forward rotations of the sheet feed roller 21feed the print paper P accommodated in the sheet feed tray 20 into theconveying path R. The sheet feed roller 21 is rotatably provided in onetip end of the sheet feed arm 22. The sheet feed arm 22 is pivotallymovably provided to one end portion of the shaft 23 which is supportedon the frame of the image forming apparatus 1. The sheet feed arm 22pivotally moves toward the sheet feed tray 20 and urges the same by itsown weight or by resilient force of a spring or the like. A drivingforce is generated by reversible rotations of a motor (not shown)disposed in the image forming apparatus 1 and is transmitted to thesheet feed roller 21, resulting in forward rotations of the sheet feedroller 21.

The conveying path R is a space formed with guide members 51, 52, therecording section 3, and another guide members 53, 54.

A feed roller 60 is disposed in upstream of the recording section 3 inthe conveying direction. A pinch roller 61 is disposed in opposition tothe lower part of the feed roller 60. The feed roller 60 rotates by thedriving power generated by the motor of the image forming apparatus 1.The pinch roller 61 rotates following the rotations of the feed roller60. Forward rotations of the feed roller 60 and the pinch roller 61(forward rotations of the feed roller 60 and the following rotations ofthe pinch roller 61) cause the print paper P to move toward the imagerecording position “x” in the conveying path R while holding the printpaper P between the feed roller 60 and the pinch roller 61. The imagerecording position “x” is a position to carry out image recordation onthe print paper P. Transmission of the driving power generated by theforward rotations of the motor of the image forming apparatus 1 causesthe feed roller 60 to rotate forwardly, whereas transmission of thedriving power generated by the reverse rotations of the motor of theimage forming apparatus causes the feed roller 60 to rotate reversely.Incidentally, the forward rotations of the motor of the image formingapparatus 1 correspond to a first direction, and the reverse rotationsof the motor of the image forming apparatus correspond to a seconddirection.

The recording section 3 is disposed between the feed roller 60 and thedischarge roller 62 both in the conveying path R. The recording section3 includes a carriage 31, a recording head 32, a plurality of nozzles33, and a platen 34. Each nozzle 33 is fluidly connected to the relevantink cartridge 4. Note that the numbers of nozzles and the ink cartridges4 are not limited for no particular reason.

The ink cartridge 4 has a cartridge housing. The cartridge housing isattachable to the main body of the image forming apparatus 1. The inkcartridges 4 separately contain different color ink as materials usedfor image formation (for example, cyan, magenta, yellow and black). Inkis a consumable material consumed whenever printing is performed.

The carriage 31 is configured to be reciprocally movable in a directionorthogonal to the conveying direction, that is, in the widthwisedirection of the print paper P. In the image recordation on the printpaper P, the image forming apparatus 1 performs recordation of one-lineworth of image on the print paper P by ejecting ink droplets from thenozzles 33 of the recording head 32 while moving the carriage 31 in thewidthwise direction of the print paper P. The printing is performedunder the condition in which the conveyance of the print paper P isbeing stopped. As a process for starting a new line printing, the imageforming apparatus 1 feeds the print paper P for a prescribed amount bydriving the feed roller 60 and the discharge roller 62. The imageforming apparatus 1 alternately repeats the process for recordation andthe process for starting a new line printing.

As shown in FIG. 1, the recording head 32 is mounted on the carriage 1.The plurality of nozzles 33 is formed in the lower surface of therecording head 32. The recording head 32 operates to eject ink dropletsfrom the nozzles 33. The platen 34 is a rectangular, plate-shaped memberon which the print paper P is supported. Images are recorded on theprint paper P by the recording head 32 selectively ejecting ink dropletsduring the movements of the carriage 31 relative to the print paper Psupported on the platen 34.

The discharge roller 62 is disposed downstream of the recording section3 in the conveying direction. A spur 63 is disposed in opposition to theupper part of the discharge roller 62. The discharge roller 62 is drivenby the motor provided in the image forming apparatus 1. The spur 63rotates following the rotations of the discharge roller 62. Forwardrotations of the discharge roller 62 and the spur 63 (rotations of thedischarge roller 62 and the following rotations of the spur 63)discharge the print paper P onto the discharge tray 30 while holding theprint paper P between the discharge roller 62 and the spur 63.

The discharge tray 30 is disposed above the sheet feed tray 20. Thedischarge tray 30 supports the print paper P discharged by the dischargeroller 62.

<Internal Structures of Image Forming Apparatus, Ink Cartridge 4 andServer 9>

FIG. 2 is a block diagram showing essential structures of the imageforming apparatus 1, ink cartridge 4, and a server 9 according to theembodiment.

<Ink Cartridge>

The ink cartridge 4 has an ink memory 42 (an example of a first memory).Reading data from and writing data into the ink memory 42 can be done. Aflash ROM or EEPROM (registered trademark) are examples of the inkmemory 42.

The ink memory 42 has a first region 421 for storing information aboutthe ink cartridge, a second region 422, and a third region 423. Thefirst region 421 stores an ink ID. The second region 422 stores an inktype information. The third region 423 stores ink service-lifeinformation. The third region may be a data rewritable region.Incidentally, the ink ID and the ink service-life information are notrequisite information in the present disclosure.

The ink ID is, for example, a serial number uniquely assigned toindividual ink cartridge 4 for discrimination from others. The ink typeinformation indicates either a contract-dedicated ink cartridge 4 or anormal type ink cartridge 4. The “contract-dedicated cartridge” refersto an ink cartridge supplied to the user from a service provider, wherea contract to this effect has been made regarding the image formingapparatus between the user and the service provider. On the other hand,the “normal type ink cartridge” refers to an ink cartridge other thanthe contract-dedicated cartridge. For example, the normal type inkcartridge is on sale in a generally accessible market. The inkservice-life information refers to information about the residual amountof ink.

The main of the image forming apparatus has a connector 101. When theink cartridge 4 is attached to the main body of the image formingapparatus 1, the connector 101 is brought into electrical contact withthe ink memory 42, whereby the controller 80 of the image formingapparatus 1 is capable of communicating with the ink memory 42 of theink cartridge 4.

<Image Forming Apparatus 1>

The image forming apparatus 1 includes the controller 80, acommunication section 81, and a main body memory 82. The controller 80has, for example, an ASIC (Application Specific Integrated Circuit). Thecontroller 80 is electrically connected to both the main body memory 82provided in the main of the image forming apparatus 1 and thecommunication section 81. The controller 80 executes various kinds ofprocesses, thereby making the image forming apparatus 1 execute variouskinds of processes in association with printing. The controller 80 maycontrol the sheet supply portion 2, conveying roller 60, recordingsection 3, and discharge roller 62 to perform printing operation.

Incidentally, the controller 80 may have a processor, such as a CPU. Inthis case, control programs are stored in the main body memory 82 forimplementing method of image forming control. The processor operates inaccordance with the control programs, thereby making the image formingapparatus 1 perform various kinds of processes.

The controller 80 may have a computer-readable storage medium forstoring control programs. As such storage medium, “tangible medium ofthe type not temporarily storing data” can be used, such as ROM (ReadOnly Memory), tape, disk, card, semiconductor memory, programmable logiccircuit. In other words, the controller 80 has a non-transitory storagemedium storing a set of program instructions installed on and executedby the controller 80. A RAM (Random access Memory) may also be used fordeveloping the control programs therein. The control programs may besupplied to the computer through an arbitrarily selected transfer mediumcapable of transmitting the control programs (communication network orbroadcasting waves). According to one embodiment of the presentdisclosure, the transfer of the control programs can be embodied byelectronic transfer of the control programs by way of the data signalsuperposed on a carrier.

When the ink cartridge 4 is attached to the image forming apparatus 1,the ink cartridge 4 is brought to electrical connection to thecontroller 80 as shown in FIG. 2, thereby allowing the controller 80 toexecute an information retrieving process to retrieve information fromthe ink memory 42 and also an information writing process (a rewritingprocess inclusive).

The main body memory 82 is such a memory that can read informationtherefrom and write information thereinto. The main body memory 82 is,for example, configured from a flash ROM or EEPROM (registeredtrademark). The main body memory 82 has a region 821 for storing inkinformation, a region 822 where the printer ID is stored, a region 823where the contract information is stored, a region 824 where a firstupper limit information is stored, a region 823 where a second upperlimit information is stored, a region 826 where a first page numbercounter is stored, and a region 827 where a second page number counteris stored.

The ink information includes linked information about each of the inkcartridges 4 linking the ink ID read from the ink memory 42 of the inkcartridge 4, the ink type information, and the ink service-lifeinformation.

The printer ID is discriminating information for discriminating theimage forming apparatus from others. For example, a serial numberassigned to each image forming apparatus is used as the printer ID.

The contract information indicates contents of the contract of the imageforming apparatus 1. More specifically, the contract informationindicates whether the image forming apparatus 1 is under the contract ornot under the contract (normal image forming apparatus 1). According tothe present embodiment, the contract information indicates whether theimage forming apparatus 1 is set to a contract mode or the image formingapparatus 1 is set to a normal mode. Note that the contract moderepresents that the image forming apparatus 1 is under the contractwhereas the normal mode represents that the image forming apparatus 1 isnot under the contract. The contract information may be rewritten to anew content via the server 9 in the case where the user of the imageforming apparatus 1 changes the contents of the contract.

According to the embodiment, the contract information indicates that theimage forming apparatus 1 is either under the contract mode or under thenormal mode. In the contract mode, the contract information furtherindicates whether the printing can be performed in the off-line state orthe print cannot be performed in the off-line state. When the imageforming apparatus 1 is under the contract mode, the image formingapparatus 1 can use not only the contract-dedicated cartridge but alsonormal type cartridge. On the other hand, when the image formingapparatus 1 is under the normal mode, the image forming apparatus 1cannot use the contract-dedicated cartridge but can use the normal typecartridge.

The contract mode may have a plurality of kinds. For example, the upperlimit of the number of printable pages represented by the first upperlimit information and the upper limit of the number of the printablepages represented by the second upper limit information may increase ordecrease according to the kind of the contract mode. The first upperlimit information and the second upper limit information will bedescribed later. For example, “first contract mode” and “second contractmode” may be defined such that the upper limit of the number ofprintable pages represented by the first upper limit information and theupper limit of the number of printable pages represented by the secondupper limit information for the “first contract mode” are larger thanthose for the “second contract mode”. Further, when the contract mode isset to the image forming apparatus 1, the contract information mayinclude information about the kind of the contract mode as well.

More specifically, according to the present embodiment, the contractinformation represents either one of the “contract mode”, “contract modeand off-line printing being stopped”, and “normal mode”. The “contractmode” represents a mode in which the image forming apparatus 1 is underthe contract, and printing can be performed using the contract-dedicatedcartridge. The “contract mode and off-line printing being stopped”represents a mode in which the image forming apparatus 1 is under thecontract, print can be performed using the contract-dedicated cartridge,and additionally printing cannot be performed in the off-line state. The“normal mode” represents a mode in which either no contract is made tothe image forming apparatus 1 or the contract-dedicated consumablematerial or replaceable part cannot be used. Thus, according to thepresent embodiment, the main body memory 82 can store the contractinformation that indicates the contents of the contract and additionallyindicates whether the image forming apparatus 1 is currently beingcapable of performing printing.

The first upper limit information represents information indicating aprintable page number determined in accordance with the kind of thecontract mode. More specifically, the first upper limit informationrepresents an upper limit of the number of pages that the image formingapparatus 1 can print during a period of time determined in thecontract. The “period of time determined in the contract” is not limitedto a particular duration. The duration may be, for example, one month.When the contents of the contract (that is, the contract mode) of theimage forming apparatus 1 are changed, the first upper limit informationmay be rewritten via the server 9. Hereinafter, the upper limit of thenumber of pages represented by the first upper limit information willoccasionally be referred to as “first upper limit page number”.

When the image forming apparatus 1 is in the normal mode, the upperlimit of the page number represented by the first upper limitinformation may be set to none (no limitation) or maximum. By sosetting, the image forming apparatus 1 operates in the normal mode to becapable of printing without any limitation in print number insofar asnormal type ink cartridge 4 is used.

The second upper limit information indicates the upper limit of theprintable page number when the image forming apparatus 1 is inthe-off-line state. More specifically, the second upper limitinformation indicates the upper limit of the number of pages that theimage forming apparatus can print when the image forming apparatus 1 isin the-off-line state. Similarly to the first upper limit information,when the contents of the contract (kind of the contract mode) of theimage forming apparatus 1 are changed, the second upper limitinformation may be rewritten via the server 9. When the image formingapparatus 1 is in the normal mode, the upper limit of the printable pagenumber represented by the second upper limit information may be set tonone (no limitation) or maximum. By so setting, the image formingapparatus 1 operates in the normal mode to be capable of printingwithout any limitation in print number insofar as normal type inkcartridge 4 is used. Hereinafter, the upper limit of the printable pagenumber represented by the second upper limit information willoccasionally be referred to as “second upper limit page number”.

Each of the first upper limit page number and the second upper limitpage number is not limited to a particular value. However, it isdesirable that the first upper limit page number be greater than thesecond upper limit page number.

The first page number counter is one example of the total printed pagenumber information. The first page number counter is such a counter thatcounts the total number of pages that are printed irrespective of theconnection status in the network of the image forming apparatus 1. Inthe present embodiment, the first page number counter counts the numberof pages printed during a predetermined period of time determined in thecontract of the image forming apparatus 1. Hereinafter, the countedvalue counted by the first page number counter will occasionally bereferred to as “first printed page number”.

The second page number counter is an example of the printed page numberinformation. The second page number counter counts the number of pagesprinted in an off-line status. In other words, the second page numbercounter is information indicating the number of pages in the off-linestate. When the image forming apparatus 1 shifts from the off-line stateto the on-line state, the second page number counter is reset to aninitial value. The initial value of the second page number counter iszero (0). Hereinafter, the count value in the second page number counterwill occasionally be referred to as “second printed page number”.

Other than those described above, the main body memory 82 may store, forexample, information indicting cumulative printed page number printed bythe image forming apparatus 1.

The communication section 81 is a communication interface for thecommunication between the image forming apparatus 1 and the server 9.The communication section 81 outputs a request received from the server9 to the controller 80. Here, the “request” is for requesting the imageforming apparatus 1 to send status data of the image forming apparatus 1to the server 9. The communication section 81 transmits the status datainputted from the controller 80 to the server 9. Here, the “status data”refers to data with regard to the operating status of the image formingapparatus 1 and includes at least printer discriminating information,and further at least one of count value in the first page number counterand the cumulative printed page number printed by the image formingapparatus 1. Other than those mentioned above, the status data mayinclude the count value of the second page number counter.

<Server 9>

The server 9 operates as a managing apparatus managing one or more imageforming apparatuses 1. While the server 9 is connected to only one imageforming apparatus 1 in the example shown in FIG. 1, the server 9 may beconnected so as to be communicable with a plurality of image formingapparatuses 1.

The server 9 includes a server communication unit 91, a server memory92, and a server control unit 93. The server communication unit 91 is acommunication interface for communications between the server 9 and theimage forming apparatus 1. The server communication unit 91 transmitsthe request inputted from the server control unit 93 to the imageforming apparatus 1. The server communication unit 91 receives thestatus data transmitted from the image forming apparatus 1 in responseto the request, and outputs the received status data to the servercommunication unit 91.

The server control unit 93 is a CPU (Central Processing Unit) forperforming an overall control on the server 9. The server control unit93 creates, at prescribed timings, requests for requesting the imageforming apparatus 1 to send status data of the image forming apparatus 1to the server 9, and outputs the created requests to the servercommunication unit 91.

Further, the server control unit 93 stores the status data received viathe server communication unit 91 in the server memory 92. Morespecifically, the server control unit 93 stores the status datatransmitted from the image forming apparatus 1 in the server memory 92as printer information.

The server memory 92 is a storage device for storing data needed tooperate the server 9. The server memory 92 has a region 921 for storingthe printer information. The printer information is data includingvarious pieces of information regarding the image forming apparatus 1formulated en bloc. The printer information of the plurality of imageforming apparatuses is stored separately on an apparatus basis. Theprinter information includes at least printer ID, contract information,and status data. The printer information may additionally include, forexample, mode number, and manufactured year/month/date.

<Flows of Various Kinds of Processes>

Next, flows of various kinds of processes executed by the controller 80of the image forming apparatus 1 will be described while referring toFIG. 3 through FIG. 6. The controller 80 of the image forming apparatus1 is executing a connection monitoring process while power source of theimage forming apparatus 1 is in the ON state. The connection monitoringprocess is a process for monitoring whether the image forming apparatus1 is in a state that the image forming apparatus 1 is connectable to thenetwork.

Additionally, the image forming apparatus 1 executes a term renewalprocess every predetermined period of time. The term renewal process isa process for renewing or updating the term for the contract when theperiod of time specified in the contract of the image forming apparatus1 is expired.

In response to a print job received through an input section, the imageforming apparatus 1 executes a print process for the received input job.Hereinafter, a process executed from receipt of the print job until theend of print corresponding to the received print job will occasionallybe referred to as “print associated process”.

<Connection Monitoring Process>

FIG. 3 is a flowchart illustrating a flow of the connection monitoringprocess. First of all, the controller 80 determines whether the imageforming apparatus 1 is in the on-line state (S10). The on-line state isa state in which the communication section 81 of the image formingapparatus 1 is connected to the network. On the other hand, the off-linestate is the state in which the communication section 81 is incapable ofconnecting to the network. In other words, the on-line state is a statein which the communication section 81 is communicably connected to theserver communication section 91 whereas the off-line state is a state inwhich the communication section 81 is not communicably connected to theserver communication section 91.

When the controller 80 does not determine that the image formingapparatus 1 is in the on-line state (S10: NO), that is, when the imageforming apparatus is in the off-line state, the controller 80 does notexecute any particular processes and waits until a timing at which theconnection monitoring process is executed again.

On the other hand, when the controller 80 determines that the imageforming apparatus 1 is in the on-line state (S10: YES), the controller80 resets the second page number counter stored in the main body memory82 to zero (0) (S11: reset process). Incidentally, in the case where thesecond page number counter has already been zero (0), the process in S11may be dispensed with by the controller 80.

Resetting the second page number counter at the time of the on-linestatus enables the controller 80 to start counting the print number inthe off-line state from zero (0) when the status of the image formingapparatus 1 is changed to the off-line state.

The timing at which the connection monitoring process is executed by thecontroller 80 and an interval by which the connection monitoring processis executed are not limited in particular. However, when thecommunication connection status of the image forming apparatus 1 isshifted from the on-line state to the off-line state or vice versa, itis desirable that the connection monitoring process be executed at arelevant frequency capable of detecting the status of the communicationconnection without delay.

<Term Renewal Process>

FIG. 4 is a flowchart illustrating the flow of the term renewal process.

The controller determines whether a process for a renewal term hasstarted (S20). The start of the renewal term means that after the termspecified in the contract has expired and the succeeding term hasstarted. The controller 80 may determine that the term has newly startedby recognizing the day and time by, for example, a timer (not shown)provided in the image forming apparatus 1. Alternatively, the controller80 may determine that the term is newly started based on the informationabout the day and time supplied from the server 9 through thecommunication section 81.

When the controller 80 does not determine that the renewal term hasstarted (S20: NO), the controller 80 waits for the timing at which theterm renewal process is executed again. On the other hand, when thecontroller 80 determines that the renewal term has started (S20: YES),the controller 80 resets the first page number counter stored in themain body memory 82 (S21).

<Print Associated Process>

FIG. 5 is a flowchart illustrating a flow of the print associatedprocess. A series of processes shown in the flowchart of FIG. 5 startswith receipt of the print job by the image forming apparatus 1 operatingas a trigger.

When the print job is received, the controller 80 reads the contractinformation stored in the main body memory 82 (S30), whereupon thecontroller 80 determines whether a condition that the image formingapparatus 1 cannot perform printing in the off-line state is satisfied(S31). When the controller 80 determines that the printing cannot beperformed with the image forming apparatus 1 being in the off-line state(S31: YES), the controller 80 notifies the user that the image formingapparatus 1 is unable to perform printing (S33). For example, thecontroller 80 displays a message on the display section of the imageforming apparatus 1 notifying that the printing cannot be performed.

As will be described in detail later, when the image forming apparatus 1is in the off-line state, the process in FIG. 5 repeatedly executes afirst print availability determining process (S41). When the off-linestate is shifted to the on-line state, the controller 80 escapes fromthe loop of the process of S41 and updates the contract information suchthat the updated contract information indicates that the image formingapparatus 1 can perform printing (S416 in FIG. 6 which will be describedlater). As such, when the print associated process is started in theon-line state of the image forming apparatus 1, the controller 80definitely determines that S31 is “NO”.

On the other hand, when the controller 80 does not determine that theimage forming apparatus 1 is incapable of printing in the off-line state(S31: NO), the controller 80 subsequently reads the value of the firstpage number counter and the first upper limit page number stored in themain body memory 82. Then, the controller 80 determines whether thetotal value of the first printed page number and the print page numberdefined in the print job to be executed is greater than or equal to thefirst upper limit page number (S32: second determining process).

The determination of “YES” made by the controller 80 in S32 indicatesthat execution of the print job defined in the print job intended toexecute from now on will result in reaching the first upper limit pagenumber that is printable within the term specified in the contract ofthe image forming apparatus 1. Accordingly, when determination is madeto “YES” in S32, the controller 80 does not execute the successive printprocess and notifies the user that printing cannot be performed usingthe display section (S33).

The contents of the notification made when S31 is “YES” and the contentsof the notification made when S32 is “YES” may be different from eachother. For example, when the determination made in S31 is “YES”, thecontroller 80 may display in the display section a message reading“Printing cannot be performed in the off-line state”. On the other hand,when determination made in S32 is “YES”, the controller 80 may displayin the display section a message reading “Printing is no longerperformable because the upper limit page number printable within thecontract term will be reached”.

On the other hand, determination made in S32 by the controller 80 being“NO” indicates that execution of the print process defined in the printjob to be executed from now on will not reach the first upper limit pagenumber printable within the term specified in the contract of the imageforming apparatus 1. Accordingly, when determination made in S32 is“NO”, the controller 80 starts the print process defined in the printjob.

After start of the print job, the processes in S35 to S43 are executedby the controller 80 every time when one sheet of paper is printed.First of all, the controller 80 refers to the print job and determineswhether the print mode for one sheet of paper to be printed from now onis double-sided printing (S35). When the controller 80 determines thatthe double-sided print is to be performed (S35: YES), the controller 80performs one sheet of printing in double-sided print (S36) andincrements the first page number counter of the main body memory 82 bytwo (two sheets of paper) (S37: increment process).

On the other hand, when the controller 80 does not determine that thedouble-sided print is to be performed (S35: NO), the controller 80performs one sheet of printing in single-sided print (S38) andincrements the first sheet number counter of the main body memory 82 byone (one sheet of paper) (S39: increment process).

Subsequently, the controller 80 confirms that the image formingapparatus 1 is in the off-line state (S40). When the controller 80determines that the image forming apparatus 1 is not in the off-linestate (S40: NO), that is, determines to be in the on-line state, thecontroller 80 performs subsequent one sheet of printing. That is, thecontroller returns to S35 and repeatedly executes the relevant process.When the controller 80 completes printing of all of the pages defined inthe print job, the controller 80 escapes from the print process loop inS34 and ends the process (S44).

On the other hand, when the controller 80 determines that the imageforming apparatus 1 is in the off-line state (S40: YES), the controller80 executes a first print availability determining process (S41). Thefirst print availability determining process indicates a determiningprocess for determining whether print can be performed or not in theoff-line state. Details of the first print availability determiningprocess will be described later.

As a result of printability determination, when the controller 80determines that printing cannot be performed in the off-line state (S42:YES), the controller 80 notifies the user of the print incapabilitythrough the display section or the like (S43). The notification contentsin S43 may be different from those notified in S33. Note that theprocess executed in S43 is not requisite. After execution of S43, thecontroller 80 executes the first print availability determining processagain (S41). That is, the controller 80 interrupts printing and executesa loop of S41 through S43 until the second page number counter is resetin response to the off-line state being changed into the on-line state(S11 in FIG. 3).

In the case where the printing performed in S36 or S38 corresponds tothe printing for the last sheet of paper defined in the print job, whenthe determination made in S42 is YES, the processes fall in the loop inS41 through S43. Accordingly, even though the image forming apparatus 1accepts a new print job, the print associated processes with respect tothe new print job does not start insofar as the results of determinationin S41 indicate that print can be performed in the off-line state. Withsuch processes, even though printing for all sheets of paper defined inthe print job is completed in S36 or S38, printing for the next printjob can be stopped.

On the other hand, when the controller 80 determines that printing canbe performed as a result of the first print availability determinationprocess (S42: NO), the controller 80 performs printing of the subsequentone sheet. That is, the controller 80 returns to S35 and repeatedlyexecutes the processes S35 et seq. Incidentally, when the controllercompletes printing to all pages defined in the print job, the controllerescapes from the print process loop in S34 and ends the processes.

<First Print Availability Determining Process>

FIG. 6 is a flowchart illustrating a flow of first print availabilitydetermining process. First of all, the controller 80 reads the ink typeinformation stored in the main body memory 82, so that the image formingapparatus 1 can recognize that any of the ink cartridges 4 attached tothe image forming apparatus 1 is the contract-dedicated cartridge(S410).

When the controller 80 recognizes that at least one of the cartridges isthe contract-dedicated cartridge (S410: YES), the controller 80increments the second page number counter by the same number as thatincremented in the first page number counter in S37 or S39 of FIG. 5(S411). More specifically, the controller 80 increments the second pagenumber counter by two in the case of double-sided printing, andincrements the second page number counter by one in the case of one sideprinting.

Subsequently, the controller 80 determines whether the second printedpage number that is obtained through incrementing in S411 is greaterthan or equal to the second upper limit page number (S412: firstdetermining process). When the controller 80 determines that the secondprinted page number is greater than or equal to the second upper limitpage number (S412: YES), the controller 80 determines that printing inthe off-line state to be executed in S412 et seq cannot be performed(S413). The controller 80 updates the contract information stored in themain body memory 82 to the context that the contract is being effectiveand the off-line printing is being stopped (S414: print inhibitionprocess). In other words, the controller 80 inhibits execution ofprinting in step S412 et seq in the off-line state. This can limit thenumber of pages that the image forming apparatus 1 can print in theoff-line state.

On the other hand, when the controller 80 determines that the secondprinted page number is smaller than the second upper limit page number(S412: NO), the controller 80 determines that printing in the off-linestate can be performed (S415). The controller 80 updates the contractinformation stored in the main body memory 82 to “normal” (S416: printapproval process). In other words, the controller 80 approves printingin the off-line state to be executed in S412 et seq. According to thepresent embodiment, the number of printed pages is counted each time aprint process is executed on one sheet of paper. Regardless of whetherthe printing is in the double-sided printing or in the one sideprinting, after the print process is executed on one sheet of paper, theimage forming apparatus 1 determines whether the execution of theprinting on the one sheet has caused the number of printed pages toreach the second upper limit page number, which indicates the upperlimit of the page number printable by the image forming apparatus 1 inthe-off-line state. Therefore, for example, even though the second upperlimit page number will be reached with one more page, the image formingapparatus 1 does not determine whether the second upper limit pagenumber is reached after only one side of a sheet printed and before theother side of the sheet is printed. In other words, the image formingapparatus 1 does not determine that the second upper limit page numberis reached while one sheet is being printed with the double-sideprinting. Hence, the image forming apparatus can manage the number ofprint pages during the off-line state without losing the user'sconvenience as much as it can be. According to the present embodiment,in a state where the image forming apparatus 1 is in the off-line state,the image forming apparatus 1 starts performing printing when the sum ofthe total printed page number and the print page number defined by theprint job is greater than or equal to the upper limit of the printablepage number which is defined in accordance with the contents of thecontract set in the image forming apparatus, and thereafter determineswhether the number of printed pages has reached the number of printablepages that can be printed in the off-line state.

When the controller 80 does not determine that at least one inkcartridge is the contract-dedicated cartridge (S410: NO), that is, allcartridges are the normal type cartridges, the controller 80 determinesthat printing can be performed in the off-line state (S415), and updatesthe contract information in the main body memory 82 to “normal” (S416).Stated differently, the controller 80 approves printing in the off-linestate to be executed in S15 et seq. By so doing, printing in theoff-line state can be performed by replacing all the cartridges to thenormal ones even in the image forming apparatus 1 under the contract.Accordingly, user-friendliness can be enhanced.

Second Embodiment

Another embodiment of the present disclosure will be describedhereinafter. For the sake of convenience of description, the membersdescribed in the above embodiment and those having the same functionwill be denoted by the same reference numerals and duplicate descriptionwill not be repeated.

The image forming apparatus 1 may be a laser printer. In the laserprinter embodying the image forming apparatus 1, a drum cartridge and atoner cartridge are attached to the image forming apparatus 1, ratherthan attaching the ink cartridge 4. Note that there is no particularlimitation in the number of each of the drum cartridge and the tonercartridge to be attached to the image forming apparatus 1. Also, thereis no particular limitation in the structure of each of the drumcartridge and the toner cartridge.

For example, the drum cartridge and the toner cartridge may be thecartridges independent one from the other. Alternatively, the drumcartridge and the toner cartridge may be integrally structured byattaching the toner cartridge to the drum cartridge. The toner cartridgeis inserted into the housing of the image forming apparatus 1 togetherwith the drum cartridge in the state that the toner cartridge isattached to the drum cartridge.

For the case in which the drum cartridge and the toner cartridge areindependent one from the other, it is desirable that the structure ofeach of the drum cartridge and the toner cartridge be either one of thefollowing three categories.

One category may be structured in such a manner that the drum cartridgehas a cartridge housing in which a photosensitive drum, a drum memory,and a developing roller are provided. The toner cartridge may have acartridge housing in which a toner memory is provided. The cartridgehousing of the toner cartridge accommodates toner therein. In theinterior of the drum cartridge, the outer peripheral surface of thedeveloping roller is in contact with the surface of the photosensitivedrum, so that developing agent (that is, toner) is deposited on thesurface of the photosensitive drum. The toner deposited thereon istransferred onto a sheet of paper by virtue of a transfer belt. Dataindicated in the print job is thus printed.

The second category may be structured in such a manner that thephotosensitive drum and the drum memory are provided within thecartridge housing of the drum cartridge. The developing roller may beprovided within the cartridge housing of the toner cartridge. In theinterior of the drum cartridge, the outer peripheral surface of thedeveloping roller is in contact with the outer surface of thephotosensitive drum.

The third category may be structured to attach a developer cartridgehaving a developing roller separate from the drum cartridge and thetoner cartridge. In such a case, the drum cartridge includes a cartridgehousing, a photosensitive drum, and a drum memory. The toner cartridgehas a cartridge housing and a toner memory. The cartridge housing of thetoner cartridge accommodates toner therein. In the third category, threecartridges, that is, the drum cartridge, the toner cartridge, and thedeveloping cartridge, are inserted into the main body.

The drum memory stores, for example, a drum ID, a drum type information,and a drum service-life information. The drum ID and the drumservice-life information are not requisite information in thisdisclosure. The drum type information indicates whether the drumcartridge is a contract-dedicated drum cartridge or a normal drumcartridge.

The toner memory stores, for example, a toner ID, a toner typeinformation, and a toner service-life information. Note that the tonerID and the toner service-life information are not requisite informationin this disclosure. The type information indicates whether the tonercartridge is the contract-dedicated cartridge or the normal tonercartridge.

In the laser printer embodying the image forming apparatus 1, the mainmemory stores the drum information and the toner information in lieu ofthe ink information. The drum information is information linking thedrum ID read from the drum memory of each drum cartridge, the drum typeinformation, and the drum service-life information. The tonerinformation is information linking the toner ID read from the tonermemory of each toner cartridge, the toner type information, and thetoner service-life information.

Specifically, the drum cartridge and the toner cartridge may be anintegral type cartridge such that the drum cartridge and the tonercartridge are integrally structured. Such an integral type cartridgeincludes a cartridge housing, a photosensitive drum, a memory, and adeveloping roller. In the interior of the integral type cartridge, theouter peripheral surface of the developing roller is in contact with theouter peripheral surface of the photosensitive drum. The cartridgehousing of the integral type cartridge accommodates toner therein. Thememory of the integral type cartridge stores various kinds ofinformation stored in the aforesaid drum memory and the toner memory.

To the laser printer embodying the image forming apparatus 1, the flowof the processes shown in FIGS. 3 through 6 are equally applicable.Concretely, in the laser printer embodying the image forming apparatus1, the word of the ink cartridge 4 appearing in FIGS. 3 through 6 may bereplaced with a drum cartridge and toner cartridge (or integral typecartridge).

For the laser printer embodying the image forming apparatus 1, inkmemory 42 appearing in FIGS. 3 through 6 may be replaced with the drummemory and the toner memory. Further, in the laser printer embodying theimage forming apparatus 1, the word ink type information appearing inFIGS. 3 through 6 may be replaced with the drum type information and thetoner type information. The image forming apparatus according to thepresent embodiment takes similar effects to the image forming apparatus1 according to the first embodiment.

In the first and second embodiments, determination can be made as towhether the number of printed pages has reached the upper limit pagenumber or more as specified in the second upper limit information whenthe image forming apparatus 1 is brought into the off-line state. Due tosuch determination, it is possible to determine whether performing onesheet printing results in reaching the printable upper limit page numberin the off-line state whichever double-sided printing or one-sideprinting is performed with the image forming apparatus 1. In amodification, the main body memory 82 of the image forming apparatus 1may store the first upper limit information indicating the upper limitof the printable page number set in the image forming apparatusdepending upon the contents of the contract, and the total printed pagenumber information indicating the total number of pages that has beenprinted by the image forming apparatus 1. Furthermore, the controller 80may execute a print process for printing one or more sheets inaccordance with the print job, an increment process for incrementing thetotal printed page number information by one each time when one sideprinting for one sheet is performed, and by two each time whendouble-sided printing for one sheet is performed in the print process,and a second print availability determining process for determining,after execution of the increment process, whether the printed sheetnumber indicated by the total printed page number information is greaterthan or equal to the upper limit sheet number indicated by the firstupper limit information. In a further modification, the controller 80may execute a print inhibition process for inhibiting printing in thesubsequent print process in the case where the second print availabilitydetermining process indicates that the total printed page numberindicated by the total printed page number information is greater thanor equal to the first upper limit sheet number indicated by the firstupper limit information.

Next, flows of processes executed by the controller 80 of the imageforming apparatus according to one example of the modification will bedescribed while referring to FIGS. 7 and 8. In the followingdescription, the same steps as those described in the above-mentionedembodiments is assigned the same reference numeral and the descriptionmay be omitted.

<Print Associated Process>

FIG. 7 is a flowchart illustrating a flow of a print associated processaccording to one example of the modification. A series of processesshown in the flowchart of FIG. 7 starts with receipt of the print job bythe image forming apparatus 1 operating as a trigger.

When the print job is received, the controller 80 reads the contractinformation stored in the main body memory 82 (S30), whereupon thecontroller 80 determines whether a condition that the image formingapparatus 1 cannot perform printing is satisfied (S51). Morespecifically, the controller 80 determines whether the printed pagenumber has reached the first upper limit number that is printable withinthe term specified in the contract of the image forming apparatus 1, orthe printed page number has reached the second upper limit number thatis the printable page number when the image forming apparatus 1 is inthe-off-line state. When the controller 80 determines that the printingcannot be performed with the image forming apparatus 1 (S51: YES), thatis, when the printed page number has reached the first upper limitnumber or the second upper limit number, the controller notifies theuser that the image forming apparatus 1 is unable to perform printing(S52). For example, the controller 80 displays a message on the displaysection of the image forming apparatus 1 notifying that the printingcannot be performed.

On the other hand, when the controller 80 does not determine that theimage forming apparatus 1 is incapable of printing (S51: NO), that is,when the printed page number has not yet reached the first upper limitnumber and the second upper limit number, the controller 80 performs theprint process defined in the print job (S34). Since the contents of thesteps S35 to S39 are the same as those of the steps S35-S39 in theabove-described embodiments, description of S35-S39 are omitted.

After performing the step S37 or S39 (increment process), the controller80 executes the second print availability determining process (S60). Thesecond print availability determining process indicates a determiningprocess for determining whether print can be performed or not. Detail ofthe second print availability process will be described later.

As a result of the second printability determination process of S60,when the controller 80 determines that printing cannot be performed(S61: YES), the controller 80 notifies the user of the printincapability through the display section or the like (S62). After thestep S62, the controller ends the process. On the other hand, when thecontroller 80 determines that printing can be performed as a result ofthe second print availability determination (S61: NO), the controllerexecutes steps S40 to S44. Since the contents of the steps S40 to S44are the same as those of the steps S40-S44 in the above-describedembodiments, description will be omitted.

<Second Print Availability Process>

FIG. 8 is a flowchart illustrating a flow of the second printavailability determining process of S80. When the second printavailability determining process starts, First, the controller 80 readsthe ink type information stored in the main body memory 82 so that theimage forming apparatus 1 can recognize whether any of the inkcartridges 4 attached to the image forming apparatus 1 is thecontract-dedicated cartridge (S610).

When the controller 80 recognizes that at least one of the cartridges isthe contract-dedicated cartridge (S610: YES), the controller 80determines whether the first printed page number that is obtainedthrough incrementing in S37 or S39 in FIG. 7 is greater than or equal tothe first upper limit page number (S611). When the controller 80determines that the first printed page number is greater than or equalto the first upper limit page number (S611: YES), the controller 80determines that printing to be executed in S611 et seq cannot beperformed (S612). Then, the controller 80 updates the contractinformation stored in the main body memory 82 to the context that thecontract is being effective and printing is being stopped (S613: printinhibitation process). In other words, the controller 80 inhibitsexecution of printing in step S611 et seq.

On the other hand, when the controller 80 determines that the firstprinted page number is smaller than the first upper limit page number(S611: NO), the controller 80 determines that printing can be performed(S614), and updates the contract information stored in the main bodymemory 82 to “normal”. In other words, the controller 80 approvesprinting to be executed in S611 et seq.

When the controller 80 does not determine that at least one inkcartridge is the contract dedicated cartridge (S610: NO), that is, whenall cartridges are the normal type cartridges, the controller 80determines that printing can be performed (S614), and updates thecontract information in the main body memory 82 to “normal”.

<Software Implemented Example>

The control blocks of the image forming apparatus 1 and the server 9 maybe implemented by logic circuits (hardware) formed on an integratedcircuit (IC chip) or by way of a software solution.

In the latter case, each of the image forming apparatus 1 and the server9 includes a computer for executing program commands that are softwarefor implementing each function. Each computer in the image formingapparatus 1 and the server 9 includes, for example, one or moreprocessors and a storage medium readable by the computer storing theprograms. In such a computer, the object of the present disclosure canbe achieved by reading the programs from the storage medium andexecuting the same by the processor. As such a processor, a CPU (CentralProcessing Unit) can be used, for example. As the storage medium, a“tangible medium not provided with a temporarily data storingcapability” can, for example, be employ, such as ROM (Read Only Memory),a tape, a disk, a card, a semiconductor memory, or a programmable logiccircuit. In addition, a RAM (Random Access Memory) for developing theprograms may further by provided. The programs may be supplied to thecomputer through an arbitrarily selected program transferable transfermedium (communication network or broadcasting waves). In one example ofthe present disclosure, the supply of the programs may be implemented inthe form of a data signal in which the programs are embedded in acarrier wave realized by an electronic transmission.

The present disclosure is not limited to the above-describedembodiments, and various modifications can be made within the scope ofthe claimed coverage. It should be noted that further embodiments thatcan be attained by combining technical measures disclosed in differentembodiments are also within the technical scope of the presentdisclosure.

What is claimed is:
 1. An image forming apparatus comprising: aninterface configured to communicate with a network; a main body memoryconfigured to store therein: a first upper limit information indicatingan upper limit of a printable page number that is defined in accordancewith contents of a contract set in the image forming apparatus; a secondupper limit information indicating an upper limit of a printable pagenumber that the image forming apparatus is allowed to print in a statewhere the image forming apparatus is in an off-line state where theinterface is incapable of connecting with the network; and a printedpage number information indicating a printed page number printed by theimage forming apparatus in the off-line state; and a controllerconfigured to: in a state where the interface is in the off-line state,perform printing to print one or more sheets according to a print job;when one sheet is printed, increment the printed page number informationby one in a case where the one sheet of paper is printed on one sideprinting, and increment the printed page number information by two in acase where the one sheet of paper is printed on double-sided printing;and after the printed page number information is incremented, determinewhether the printed page number information is greater than or equal tothe second upper limit page number.
 2. The image forming apparatusaccording to claim 1, wherein, in a case where the controller determinesthat the printed page number information is greater than or equal to thesecond upper limit page number, the controller inhibits printing in theoff-line state afterward.
 3. The image forming apparatus according toclaim 1, wherein, in a case where the state of the interface shifts fromthe off-line state to an on-line state where the interface is connectedto the network, the controller resets the printed page numberinformation to zero.
 4. The image forming apparatus according to claim3, further comprising a main body casing formed with an opening, throughwhich one or more cartridge is mountable in the main body casing, eachcartridge having a first memory storing therein type informationindicating which of a contract-dedicated cartridge and a normalcartridge the each cartridge is, wherein, in a case where the typeinformation of all of the one or more cartridge mounted to the main bodycasing indicates that all the one or more cartridge is the normalcartridge, the controller allows printing in the off-line stateafterward.
 5. The image forming apparatus according to claim 1, whereinthe main body memory stores a total printed page number informationindicating a total printed page number that are printed irrespective ofthe connection status of the interface with the network, and wherein thecontroller is configured to: determine whether a sum of the totalprinted page number and a print page number defined by the print job isgreater than or equal to the upper limit of the printable page numberindicated by the first upper limit information; and in a case where thesum of the total printed page number and the print page number definedby the print job is smaller than the upper limit of the printable pagenumber indicated by the first upper limit information, perform theprinting of the print job.
 6. The image forming apparatus according toclaim 1, wherein the main body memory stores contract informationindicating the contents of the contract set for the image formingapparatus, the contract information indicating either one of: a firstmode in which the image forming apparatus is under the contract andprinting is allowed to be performed in the off-line state; a second modein which the image forming apparatus is under the contract and printingis not allowed to be performed in the off-line state; and a third modein which the image forming apparatus is not under the contract.
 7. Theimage forming apparatus according to claim 1, further comprising aprinting unit configured to perform printing on a sheet, wherein, in thestate where the interface is in the off-line state, the controller isconfigured to cause the printing unit to perform the printing.
 8. Theimage forming apparatus according to claim 1, wherein, every time whenone sheet is printed by the image forming apparatus, the controller isconfigured to increment the printed page number information by one in acase where the one sheet of paper is printed on one side printing, andincrement the printed page number information by two in a case where theone sheet of paper is printed on double-sided printing.
 9. A method forcontrolling an image forming apparatus comprising: in a state where theimage forming apparatus is in an off-line state where the image formingapparatus is incapable of connecting to a network, causing the imageforming apparatus to perform printing to print one or more sheetsaccording to a print job; when one sheet is printed, incrementing aprinted page number information by one in a case where the one sheet isprinted on one side printing, and incrementing the printed page numberinformation by two in a case where the one sheet is printed ondouble-sided printing, the printed page number information indicating aprinted page number printed in the off-line state; and after the printedpage number information is incremented, determining whether the printedpage number information is greater than or equal to an upper limit pagenumber that the image forming apparatus is allowed to print in theoff-line state.
 10. The method for controlling the image formingapparatus according to claim 9, wherein, every time when one sheet isprinted, a printed page number information is incremented by one in acase where the one sheet is printed on one side printing, and theprinted page number information is incremented by two in a case wherethe one sheet is printed on double-sided printing.
 11. An image formingapparatus comprising: an interface configured to communicate with anetwork; a main body memory configured to store therein: a first upperlimit information indicating an upper limit of a printable page numberthat is defined in accordance with contents of a contract set in theimage forming apparatus; and a total printed page number informationindicating a printed page number that are printed; and a controllerconfigured to: perform printing to print one or more sheets according toa print job; when one sheet is printed, increment the total printed pagenumber information by one in a case where the one sheet is printed onone side printing, and increment the total printed page numberinformation by two in a case where the one sheet is printed ondouble-sided printing; and after the total printed page numberinformation is incremented, determine whether the total printed sheetnumber information is greater than or equal to the upper limit of theprintable page number indicated by the first upper limit information.12. The image forming apparatus according to claim 11, wherein, in acase where the controller determines that the total printed sheet numberis greater than or equal to the upper limit of the printable page numberindicated by the first upper limit information, the controller inhibitsprinting afterward.
 13. The image forming apparatus according to claim11, further comprising a printing unit configured to perform printing ona sheet, wherein, the controller is configured to cause the printingunit to perform the printing.
 14. The image forming apparatus accordingto claim 11, wherein, every time when one sheet is printed, thecontroller is configured to increment the printed page numberinformation by one in a case where the one sheet is printed on one sideprinting, and increment the printed page number information by two in acase where the one sheet is printed on double-sided printing.